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Re: avoiding overload on port 587

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  • Tomas Macek
    ... Everyone here says me, that MUAs should send their mails through 587. I can t do that without iptables, because all the people here have Outlook Expresses
    Message 1 of 54 , Dec 3, 2012
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      On Tue, 4 Dec 2012, Robert Schetterer wrote:

      > Am 04.12.2012 08:20, schrieb Tomas Macek:
      >> On Tue, 4 Dec 2012, Reindl Harald wrote:
      >>
      >>>
      >>>
      >>> Am 04.12.2012 07:58, schrieb Tomas Macek:
      >>>>
      >>>>> 2) why would you setup a submission service that doesn't require auth
      >>>>> from MUAs?
      >>>>
      >>>> It's because they never had to. It is a historical problem. Now we
      >>>> have thousands of customers, that never had to
      >>>> authenticate, so there is no power to force them to do it now.
      >>>
      >>> than you have lost any game
      >>
      >> Still hope I didn't. My roadmap:
      >> 1) split 25 and 587 with permit_mynetworks on 587 and thus allow the
      >> people without auth to send their email to 587
      >
      >
      >>
      >> 2) by means of prerouting rule of iptables redirect sending emails from
      >> $mynetworks to 587
      >
      > dont do that, makes no sense

      Everyone here says me, that MUAs should send their mails through 587. I
      can't do that without iptables, because all the people here have Outlook
      Expresses setup with port 25 for sending emails from default
      configuration.

      Tomas
    • /dev/rob0
      ... Or better yet: replace it with postscreen. ... To clarify, I meant that if those Outlook Expresses are not yet compromised by malware, they will be, soon.
      Message 54 of 54 , Dec 4, 2012
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        On Tue, Dec 04, 2012 at 07:46:10AM -0600, /dev/rob0 wrote:
        > On Tue, Dec 04, 2012 at 11:59:01PM +1300, Peter wrote:
        > > I would still also set up port 587 on the mail.example.com
        > > IP as submission as well and try to encourage your users (at
        > > least the ones you can) to use port 587 from now on.
        >
        > What I would do, on Linux with IPv4 only, is create the submission
        > port and use an iptables redirect for the alternate IP address:
        >
        > # iptables -vt nat -A PREROUTING -p tcp --dport smtp -d \
        > mail.example.com -j REDIRECT --to-port submission
        >
        > This saves the overhead (system and administrative) of running
        > another smtpd on [mail.example.com]:25; he can leave his "smtp ...
        > smtpd" service alone in master.cf.

        Or better yet: replace it with postscreen.

        > I should also add as a reply to Stan in the other subthread: look
        > above at the first quoted paragraph: "Outlook Expresses setup with
        > ... default configuration."
        >
        > Yikes, bad news, very bad. If not doing content filtering nor
        > policy limitation of submission now, he will be soon. And possibly
        > losing his job in any case. Tomas is not in a good place right now.

        To clarify, I meant that if those Outlook Expresses are not yet
        compromised by malware, they will be, soon.
        --
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